The present invention relates to an apparatus and method for processing poultry carcasses and in particular to the separation of wings and breasts from poultry carcasses.
In the processing of poultry carcasses, it is important that the wings and breasts be separated from the poultry carcass with minimal loss and damage to useable portions of meat and assurance that the useable meat is not contaminated with bone residues.
The prior art discloses a form of poultry processing apparatus in which the front half of a poultry carcass is placed upon a cone shaped mandrel which is advanced by a moving conveyor past a variety of processing stations. An apparatus of this type is disclosed in U.S. Pat. No. 4,937,918 issued to Martin on Jul. 3, 1990 for "Inline Breast Deboner." In this type of apparatus the mandrel provides a steady rigid position on which the poultry carcass can be placed with sufficient precision for Manual cutting to proceed with further processing of the poultry carcass. The front half of the poultry carcass includes the wings, breast, back, rib cage and scapula. In addition, there is a keel bone and lying along the keel bone are the tenderloins or tenders. To complete the processing of the poultry carcass, it is necessary to separate the wing from the carcass at the shoulder joint, to tear the breast from the poultry carcass while retaining with the breast as much of the useable meat as is possible, removing the tenders from each side of the keel bone, and cutting the wings from the breast.
In addition to the problem of assuring that all of the poultry breast meat is removed from the poultry carcass, a significant problem occurs in the separation of the wing from the carcass at the shoulder joint. The shoulder joint comprises a ball and socket and is surrounded by a number of strong tendons and in particular the wing tendons. In separating the shoulder joint, it is important that the major tendons binding the wing to the poultry carcass be completely severed. In doing so, however, it is important to avoid cuts that would tend to leave portions of the breast meat remaining attached to the carcass and to avoid cutting through the bones of the shoulder joint. A cut made into the bone of the shoulder joint can result in the formation of bone chips or the release of bone marrow, either situation resulting in the loss of quality of the processed meat.
Many of the prior art techniques for separating the wing from the poultry carcass at the shoulder joint rely on the use of rotating circular knives. The rotating circular knives are also used in conjunction with straight knives to assist in the separation process. Examples of both combinations are found in U.S. Pat. No. 4,920,610, U.S. Pat. No. 5,176,564, U.S. Pat. No. 4,993,115, U.S. Pat. No. 4,769,872, U.S. Pat. No. 4,651,383, U.S. Pat. No. 4,597,136, U.S. Pat. No. 4,563,791 and U.S. Pat. No. 4,503,587.
To assist in correctly positioning the shoulder joint for severing the wing from the poultry carcass, various methods have been suggested in the prior art. For example, U.S. Pat. No. 4,207,653 issued to Gasbarro on Jun. 17, 1980 for "Automatic Wing Cutting Apparatus" discloses a rotatable drum-like wing retaining member with spaced wing receiving grooves along the outer surface. Spaced slots in the retaining member contain knives for selectively severing the wing at desired locations. U.S. Pat. No. 5,083,974 issued to Martin, et al. on Jan. 28, 1992 for "Turkey Breast Deboner" discloses a rest having a relief in its upper surface to locate the shoulder joint. A rotary cup knife is then used to separate the wing from the breast. Both Gasbarro and Martin are directed to the problem of cutting the wing from the breast fillet. Neither addresses the problem outlined above of separating the wing from the poultry carcass at the shoulder joint without damage to useable meat.
The use of a rotary cup knife to separate the wing from the poultry carcass is not disclosed in the prior art. As noted above, U.S. Pat. No. 5,083,974 discloses the use of a rotary cup knife to separate a poultry wing from the attached poultry breast after the combination of the wing and attached breast have been removed from the poultry carcass.
Various disclosures in the prior art have been directed to the use of a rotary cup or cylindrical knife in processing animal carcasses. Typically such rotary cylindrical or cup knives have been used in removing the anus or vent from a slaughtered animal. Typical examples of the prior art are found in U.S. Pat. No. 5,199,922, U.S. Pat. No. 4,117,570, U.S. Pat. No. 4,023,237 and U.S. Pat. No. 4,155,146. The prior art disclosures have not, however, been directed to the use of a rotary cup knife in the separation at the shoulder joint of a wing from a poultry carcass.
As discussed above, the removal of a wing and attached breast portion from a poultry carcass commences with the separation of the wing from the poultry carcass at the shoulder joint, an operation presently performed by hand. Separation of the wing and attached breast from the poultry carcass can be accomplished by tearing away the connections between the breast and the poultry carcass as disclosed in Martin's '918 patent. It is important for the successful accomplishment of this step, however, that the cuts made in preparation for the final tearing operation be made so as to ensure that the maximum amount of useable breast meat is removed from the carcass. An example of the prior art in this area is U.S. Pat. No. 4,648,155 issued to Burnett on Mar. 10, 1987 for "Chicken Deboning Apparatus and Method."